A precise control of the structure and properties is essential for gaining on the exceptional features of carbon nanotubes (CNTs) for real-life applications [1]}, [2]}, [3]}. CNTs in their pristine form are materials with negligible chemical reactivity and with low surface energy, insufficient to satisfy diverse applications [4]}, [5]}. A smart idea to regulate their properties is using different functionalization methods [6]}, [7]}, [8]}. In order to achieve high control of the material properties, different approaches have been proposed by different groups [9]}. A fascinating type of doping CNTs is by substitutionally, introducing heteroatoms into the graphitic lattice, e.g. nitrogen [10]}, [11]}, [12]}. A lot of work has been done with multiwalled N-doped CNTs over the past two decades and important applications have been found [13]}. Synthesizing single-walled (SW) tubes has imposed more challenges. While some groups have achieved this by post growth treatments of pristine nanocarbons [14]}, [15]}, [16]}, doping has also been obtained in situ, i.e. directly growing SWCNTs with incorporated heteroatoms from a specific precursor [17]}, [18]}, [19]}.
Thanks to the additional electron that N contains compared to C, using this heteroatom has gained special interest over the past years [20]}, [21]}, [22]}, since some novel electronic properties have been predicted because the N-CNT would become an n-type doped material [23]}.
The efficiency of the incorporation of N atoms within the CNTs lattice depends on several factors: choice of precursor, catalyst type, reaction temperature and time, gas flow rate and relative pressures [24]}, [25]}. Although N-CNTs have several advantages, a synthesis method for their production that ensures high quality, in terms of D/G ratio, of N-CNTs is not yet available. In fact, the quality of the materials obtained sometimes can be very low, the reproducibility is difficult and the retention of N atoms is weak and N2 gas may be trapped into the CNT [26]}, [27]}. In addition it is quite common to use toxic and corrosive precursors that are not easy to be handled. Tuning of the electronic properties of nitrogen doped single wall carbon nanotubes (N-SWCNTs) is very challenging and if achieved in a controlled manner, a very promising material will be available for applications such as in active elements of future nano-electronic devices, optical devices and sensors.
